Re: passing const char* to the string&

From:
Rolf Magnus <ramagnus@t-online.de>
Newsgroups:
comp.lang.c++
Date:
Wed, 21 Mar 2007 00:06:01 +0100
Message-ID:
<etppco$uf$02$1@news.t-online.com>
ragged_hippy wrote:

Hi,

If I have a method that has string reference as a parameter, what
happens if I pass a const char* variable to this method?


Depends.

One thought is that a temporary string will be created in the stack
and the parameter will refer to this object. Is this correct?


If the reference refers to a const std::string, yes. Otherwise, you should
get a compile error, because binding a non-const reference to a temporary
is forbidden.

Does this mean if a constructor of a class has a string reference
parameter, the temporary string that is created in the stack is
destroyed after the contruction of the object is complete?


Yes.

** Example**
e.g:
class x {
public:
    x(std::string& name);


Change that to:

     x(const std::string& name);

};

void main()


Change that to:

int main()

{
    const char* const text = "Name";
    x newObject(name);
}

Can anyone help me understand what happens during and after the
newObject is created?


Well, before newObject is created, a temporary std::string is created and
filled with "Name". This string lives while the constructor of newObject is
running and is destroyed immediately afterwards.

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